The present invention is a means and method for simulating the smoke and products of combustion of a fire which is burning at any desired temperature, without the release of any heat. It arose as the result of tests to investigate the way that smoke spreads within the passenger compartment of an airplane.
Initially, the smoke tests used a conventional theatrical smoke generator which generates a cloud of cold smoke (i.e. smoke nearly at room temperature). When the tests are performed in a real airplane, cold smoke has been traditionally used since it is obvious that setting a fire in an airplane is a rather expensive way to conduct such a test.
However, it was found that cold theatrical smoke does not spread the same way that real (i.e. hot) smoke spreads. Smoke from a fire rises up to the ceiling of the passenger compartment and then rapidly spreads fore and aft along the ceiling. By contrast, the cold theatrical smoke formed a cloud centered on the smoke generator which ultimately filled the cross section of the passenger compartment; it then gradually spread fore and aft, with its rate of spreading being a function of the rate at which the generator could produce "smoke" as well as of the direction and magnitude of the ventilation air currents near the generator.
This was a very unsatisfactory simulation since previous studies had shown that the smoke from a real fire spread along the ceiling, as discussed above. Accordingly, it was necessary to develop a smoke generator that produced cold smoke which had the same spreading properties as hot smoke from a fire.